src/endpoints/openrouter.js

import express from 'express';
import fetch from 'node-fetch';
import mime from 'mime-types';
import { readSecret, SECRET_KEYS } from './secrets.js';

export const router = express.Router();
const API_OPENROUTER = 'https://openrouter.ai/api/v1';

router.post('/models/providers', async (req, res) => {
    try {
        const { model } = req.body;
        const response = await fetch(`${API_OPENROUTER}/models/${model}/endpoints`, {
            method: 'GET',
            headers: {
                'Accept': 'application/json',
            },
        });

        if (!response.ok) {
            return res.json([]);
        }

        /** @type {any} */
        const data = await response.json();
        const endpoints = data?.data?.endpoints || [];
        const providerNames = endpoints.map(e => e.provider_name);

        return res.json(providerNames);
    } catch (error) {
        console.error(error);
        return res.sendStatus(500);
    }
});

/**
 * Fetches and filters models from OpenRouter API based on modality criteria.
 * @param {string} endpoint - The API endpoint to fetch from
 * @param {string} inputModality - Required input modality
 * @param {string} outputModality - Required output modality
 * @param {boolean} [idsOnly=false] - Whether to return only model IDs
 * @returns {Promise<any[]>} Filtered models or model IDs
 */
async function fetchModelsByModality(endpoint, inputModality, outputModality, idsOnly = false) {
    const response = await fetch(`${API_OPENROUTER}${endpoint}`, {
        method: 'GET',
        headers: { 'Accept': 'application/json' },
    });

    if (!response.ok) {
        console.warn('OpenRouter API request failed', response.statusText);
        return [];
    }

    /** @type {any} */
    const data = await response.json();

    if (!Array.isArray(data?.data)) {
        console.warn('OpenRouter API response was not an array');
        return [];
    }

    const filtered = data.data
        .filter(m => Array.isArray(m?.architecture?.input_modalities))
        .filter(m => m.architecture.input_modalities.includes(inputModality))
        .filter(m => Array.isArray(m?.architecture?.output_modalities))
        .filter(m => m.architecture.output_modalities.includes(outputModality))
        .sort((a, b) => a?.id && b?.id ? a.id.localeCompare(b.id) : 0);

    return idsOnly ? filtered.map(m => m.id) : filtered;
}

router.post('/models/multimodal', async (_req, res) => {
    try {
        const models = await fetchModelsByModality('/models', 'image', 'text', true);
        return res.json(models);
    } catch (error) {
        console.error(error);
        return res.sendStatus(500);
    }
});

router.post('/models/embedding', async (_req, res) => {
    try {
        const models = await fetchModelsByModality('/embeddings/models', 'text', 'embeddings');
        return res.json(models);
    } catch (error) {
        console.error(error);
        return res.sendStatus(500);
    }
});

router.post('/models/image', async (_req, res) => {
    try {
        const models = await fetchModelsByModality('/models', 'text', 'image');
        return res.json(models.map(m => ({ value: m.id, text: m.name || m.id })));
    } catch (error) {
        console.error(error);
        return res.sendStatus(500);
    }
});

router.post('/image/generate', async (req, res) => {
    try {
        const key = readSecret(req.user.directories, SECRET_KEYS.OPENROUTER);

        if (!key) {
            console.warn('OpenRouter API key not found');
            return res.status(400).json({ error: 'OpenRouter API key not found' });
        }

        console.debug('OpenRouter image generation request', req.body);

        const { model, prompt } = req.body;

        if (!model || !prompt) {
            return res.status(400).json({ error: 'Model and prompt are required' });
        }

        const response = await fetch(`${API_OPENROUTER}/chat/completions`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'Authorization': `Bearer ${key}`,
            },
            body: JSON.stringify({
                model: model,
                messages: [
                    {
                        role: 'user',
                        content: prompt,
                    },
                ],
                modalities: ['image', 'text'],
                image_config: {
                    aspect_ratio: req.body.aspect_ratio || '1:1',
                },
            }),
        });

        if (!response.ok) {
            console.warn('OpenRouter image generation failed', await response.text());
            return res.sendStatus(500);
        }

        /** @type {any} */
        const data = await response.json();

        const imageUrl = data?.choices?.[0]?.message?.images?.[0]?.image_url?.url;

        if (!imageUrl) {
            console.warn('No image URL found in OpenRouter response', data);
            return res.sendStatus(500);
        }

        const [mimeType, base64Data] = /^data:(.*);base64,(.*)$/.exec(imageUrl)?.slice(1) || [];

        if (!mimeType || !base64Data) {
            console.warn('Invalid image data format', imageUrl);
            return res.sendStatus(500);
        }

        const result = {
            format: mime.extension(mimeType) || 'png',
            image: base64Data,
        };

        return res.json(result);
    } catch (error) {
        console.error(error);
        return res.sendStatus(500);
    }
});